<!--轮播图-->
<template>
  <div class='xys-swiper' @mouseenter="stop" @mouseleave="start">
    <ul class="swiper-body">
      <li class="swiper-item" v-for="(item,i) in sliders" :key="i" :class="{fade:index===i}">
        <RouterLink to="/">
          <img :src="item.imgUrl" alt="">
        </RouterLink>
      </li>
    </ul>
    <a @click="toggle(-1)" href="javascript:;" class="swiper-btn prev"><i class="iconfont icon-angle-left"></i></a>
    <a @click="toggle(1)" href="javascript:;" class="swiper-btn next"><i class="iconfont icon-angle-right"></i></a>
    <div class="swiper-indicator">
      <span @click="index=i" v-for="(item,i) in sliders" :key="i" :class="{active:index===i}"></span>
    </div>
  </div>
</template>

<script setup>
import {onUnmounted, ref, watch} from "vue";
defineExpose({
  name:'xys-swiper'
})
const props=defineProps({
  sliders:{
    type:Array,
    default:()=>[]
  },
  // 自动轮播
  duration: {
            type: Number,
          default: 3000
    },
    autoPlay: {
        type: Boolean,
            default: false
      }
})
// 默认显示的图片的索引
const index = ref(0)
// 自动播放逻辑
let timer=null
const autoplay=()=>{
  clearInterval(timer)
  timer=setInterval(()=>{
    index.value++
    if (index.value>=props.sliders.length){
      index.value=0
    }
  },props.duration)
}
watch(()=>props.sliders,(newVal)=>{
  if (newVal.length&&props.autoPlay){
    index.value=0
    autoplay()
  }
},{immediate:true})
// 在自动播放的情况下,鼠标的移入移出
const stop=()=>timer && clearInterval(timer)
const start=()=>{
  if (props.autoPlay && props.sliders.length){
    autoplay()
  }
}
const toggle=(state)=>{
  const newIndex=index.value+state
  if (newIndex>=props.sliders.length){
    index.value=0
    return
  }
  if (newIndex<0){
    index.value=props.sliders.length-1
    return;
  }
//   正常
  index.value=newIndex
}
// 组件卸载,清除定时器
onUnmounted(()=>{
clearInterval(timer)
})
</script>

<style scoped lang="less">
.xys-swiper{
  width: 100%;
  height: 100%;
  min-width: 300px;
  min-height: 150px;
  position: relative;
  .swiper{
    &-body {
      width: 100%;
      height: 100%;
    }
    &-item {
      width: 100%;
      height: 100%;
      position: absolute;
      left: 0;
      top: 0;
      opacity: 0;
      transition: opacity 0.5s linear;
      &.fade {
        opacity: 1;
        z-index: 1;
      }
      img {
        width: 100%;
        height: 100%;
      }
    }
    &-indicator {
      position: absolute;
      left: 0;
      bottom: 20px;
      z-index: 2;
      width: 100%;
      text-align: center;
      span {
        display: inline-block;
        width: 12px;
        height: 12px;
        background: rgba(0,0,0,0.2);
        border-radius: 50%;
        cursor: pointer;
        ~ span {
          margin-left: 12px;
        }
        &.active {
          background:  #fff;
        }
      }
    }
    &-btn {
      width: 44px;
      height: 44px;
      background: rgba(0,0,0,.2);
      color: #fff;
      border-radius: 50%;
      position: absolute;
      top: 228px;
      z-index: 2;
      text-align: center;
      line-height: 44px;
      opacity: 0;
      transition: all 0.5s;
      &.prev{
        left: 20px;
      }
      &.next{
        right: 20px;
      }
    }
  }
  &:hover {
    .swiper-btn {
      opacity: 1;
    }
  }
}
</style>